This application claims the priority of Japanese patent document 10 188549, filed Jul. 3, 1998, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to an apparatus for supplying power from a power supply to plural electric loads mounted on a vehicle, and particularly an automobile.
In a vehicle, an electrical supply system is installed for the various kinds of the electric loads. In an automobile, for example, various power supply wire harnesses are used to supply power from a power supply such as a battery and a generator to the various electric loads.
When an electric power line (a wire harness) is used for wiring an actual vehicle, taking into consideration the labor involved in wiring and repairs, each area of the vehicle (such as an engine compartment, an interior portion of the cabin, a trunk, or a door) is connected by separating the wire harness, and using a connector. Accordingly, power is supplied to the several harnesses through the various kinds of the connectors to reach the end loads from the power supply (such as the battery).
Further, in the above described power supply system, generally one side of the power supply system is used to supply a part of a vehicle body. For this reason, a short circuit occurs only by touching the electric power line to the vehicle body.
Therefore, in the conventional vehicle power supply apparatus, since a fuse box is provided at a predetermined location in the vehicle, and further a fuse (a fusible chip for protecting against an over-current) is provided at a predetermined load system, when a short occurs in the electric power line, the power supply is isolated by the fuse, so that the apparatus is protected. Such a fuse is housed in a lower portion of a console box of the automobile, and in a fuse box which is provided to an interior portion of the trunk.
Accordingly, in the prior art, depending on its nature, the load may be connected to the power supply by a very long wire harness. Further, when the electric power line is short-circuited and fails, in order to avoid generating smoke in the electric power line before the fuse blows, it is necessary for the circuit to be able to accommodate an increase of the normal current of the electric power line up to the fuse current of the fuse. As a result, the vehicle uses a heavy gauge wire as the electric power line.
Further, if the coupling of the connector is loosened at a midway point of the wire harness and the connector fails, the power supply to the load becomes unstable. Since the wire harness is normally hidden in an inner trim (an interior mounting), the identification of the shorted portions of the electric power line and the location of a failure in connection of the connector, are difficult.
To solve the above problems, the applicants have proposed a new power supply system in an international laid-open publication No. WO 96/26570.
An object of the present invention is to provide a power supply apparatus which is highly reliable with respect to abnormalities (such as, for example, a short-circuit) of an electric power line.
Another object of the present invention is to provide a power supply apparatus in which power can be supplied using a wire harness having a comparatively low regular current.
A further object of the invention is to provide a power supply apparatus for a vehicle in which an abnormal and/or failed portion of a connection, due to a short-circuit of the wire harness, can be easily located.
Still another object of the invention is to provide a power supply apparatus which prevents unnecessarily high load current to an electric power line, and reduces consumption of electric power.
Yet another object of the invention is to provide a power supply apparatus in which a fuse and a relay are arranged in the vicinity of a control module, and power supply wiring can be shortened.
One object stated above is attained by providing a fuse and/or an electric line shutdown apparatus (for example, a relay, a self shutdown switching element, such as a circuit breaker) between the power supply and the electric load. In this manner, double protection or even a triple protection is provided against a short circuit.
Another object can be attained by means of a control unit from the power supply. To supply power to an electric load in a vehicle having a supply system in which one side is grounded to the car body of a vehicle, a conductive electric line is provided, and to connect equivalently in parallel at a respective control unit an impedance of a power line, the control unit is connected to an electric power line for a load.
According to another feature of the invention a power supply line for the control unit is arranged independently of the power supply line for the load, and an improper shutdown of the power supply for the load is controlled through a shutdown circuit.
Another object can be attained by providing an independent short sensor at plural intervals of an electric power line. When a short circuit or a failure of the connection at the connector occurs, the interval at which the failure has occurred can be determined.
Further, it is preferable to combine the present invention with a system in which a control signal is received and sent between plural control units in accordance with a communication control.
Further, in the present invention, a control module has a relay and/or a fuse between the electric power line and the electric load. The relay and/or the fuse is situated in the vicinity of the control module which controls the electric load. Preferably, a relay box and/or a fuse box is integrated into the control module in a single body, constituting a control unit.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.